During the last couple of weeks, quite a few people contacted us
about crashes, hangs and other problems with Ulysses on devices
running the beta versions of iOS 13, iPadOS and macOS Catalina.
We’ve been asked a couple of times if we couldn’t offer a beta
version of Ulysses that works fine on the new OSes.
Unfortunately, for the time being, we can’t.

From our experience with previous OS updates, we feel safe to say
that these betas are extraordinarily unstable and buggy. After
all, beta versions of operating systems are still just beta
versions — they are buggy, they are crash-prone, and they do
lose data. Whereas in recent years, it was pretty safe to install
preview versions early on, this year that’s definitely not the
case (see for example this report on Cult of
Mac).

Most impactful for us, however, is that the (great, great)
updates done to iCloud are also leading to severe problems with
the service. As iCloud is Apple’s sync service, it’s beyond our
power to solve them, of course. Some public beta users reported
synchronization outages and data loss that propagated to
devices that did not even run the beta but were just
connected via iCloud.

I’ve heard this from a bunch of developers. Right now iCloud is dangerous on the beta OSes. That’s not a complaint in and of itself; if there weren’t bugs they wouldn’t be betas. But I think it was a bad idea for Apple to release public betas at this stage. One trick I learned long ago is to install MacOS betas on an external hard drive and keep my regular startup drive unmounted while running the beta OS. But iCloud is a data store too, and you can’t unmount it.